Ingredients:

  • 3 lbs Russet potatoes, peeled
  • 1 large yellow onion, sliced into translucent rings
  • 2 cups heavy cream
  • 1 cup whole milk
  • 3 cloves garlic, smashed and minced
  • 1 tsp kosher salt
  • 0.5 tsp freshly cracked black pepper
  • 0.25 tsp ground nutmeg
  • 2 tbsp unsalted butter, cubed
  • 1 cup sharp white cheddar or Gruyère, shredded
  • 1 tbsp fresh thyme leaves

Instructions:

  1. Set a mandoline slicer to 1/8-inch thickness and slice the peeled potatoes directly into a large bowl. Do not rinse the potatoes to preserve the surface starch.
  2. Grease a 9x13 inch ceramic or glass baking dish liberally with the cubed butter.
  3. Arrange one-third of the potato slices in an overlapping shingle pattern in the dish. Scatter half of the onion rings and a pinch of salt over the layer.
  4. Repeat the layering process until all potatoes and onions are used.
  5. In a medium mixing bowl, whisk together the heavy cream, whole milk, minced garlic, nutmeg, and black pepper.
  6. Pour the cream mixture slowly over the layered potatoes until it reaches approximately three-quarters of the way up the sides of the dish.
  7. Cover the dish tightly with foil to trap steam and bake to tenderize the potatoes.
  8. Remove the foil, top with the shredded cheese and fresh thyme, and continue baking at high heat until the top achieves a deep golden-brown crust.